Pets can’t tell us when something’s wrong, so they show us—in subtle ways at first, then more obvious ones if we miss the early signs. Whether it’s a sudden mood shift, a change in how much they eat, or new habits popping up out of nowhere, behavioural changes in pets are often their way of saying, “Something’s off.” Some quirks are harmless, but others might point to pain, stress, or illness. Here are some important behaviour changes that are always worth taking seriously.
1. Sudden aggression or withdrawal
If your usually affectionate pet starts growling, hissing, hiding, or avoiding people, that’s a red flag. Sudden changes in temperament are often tied to pain or discomfort, even if there are no visible injuries. Changes like this could be anything from a sore tooth to something more serious like arthritis or illness. It’s worth booking a vet visit before assuming it’s just “a mood.”
2. Loss of interest in food
Skipping the occasional meal isn’t a big deal, but if your pet suddenly loses their appetite, and it lasts more than a day or two, it’s time to take action. For cats especially, not eating can quickly become dangerous. This might be a sign of dental pain, nausea, stress, or underlying health problems. If treats aren’t even tempting them, it’s a sign they need checking over.
3. Excessive licking or scratching
All pets groom, but when it becomes obsessive—focused on one area, causing bald patches or redness—it’s more than just a cleanliness thing. Skin conditions, allergies, pain, or even anxiety could be behind it. Dogs may lick their paws raw. Cats may focus on one leg. It’s not “just a habit” if it’s doing damage or making them uncomfortable.
4. Changes in bathroom habits
If your pet starts having accidents in the house, straining to go, or using the litter tray way more (or less) than usual, something’s up. With cats, avoiding the litter box can be a major red flag for urinary tract issues. These changes often point to physical problems like infections or bladder stones, but can also be a sign of stress or cognitive changes in older pets.
5. Pacing, panting, or restlessness
Restlessness, especially when it seems purposeless, can be a sign of pain, anxiety, or even something more serious like heart trouble. If your pet seems unsettled for no clear reason, don’t brush it off. With dogs, pacing at night or during rest times can indicate discomfort. For cats, odd nighttime energy or increased vocalisation might hint at a health change.
6. Vocalising more than usual
Is your usually quiet cat suddenly yowling at night? Is your dog barking at shadows or whining without reason? Changes in vocal behaviour often mean they’re trying to get your attention for a reason. Sometimes it’s confusion, sometimes it’s pain. Either way, if it’s new and persistent, it’s worth finding out what’s behind the noise.
7. Shaking or trembling
Shaking can happen from excitement or fear, but if it happens often and out of context, don’t ignore it. Trembling could point to pain, fever, or something neurological. Some small dogs shake more than others, but you’ll know when it seems off. If it’s paired with lethargy or a change in breathing, get it checked urgently.
8. Sleeping way more, or way less
Pets sleep a lot, but sudden increases in sleep or noticeable insomnia aren’t normal. Lethargy can be a sign of infection, metabolic issues, or even depression in some animals. If your pet goes from being lively to barely getting off the couch—or seems constantly agitated when they used to snooze peacefully—it’s worth looking into.
9. Loss of interest in toys, walks, or people
If your dog no longer wants to go for walks, or your cat isn’t batting at their favourite toy, that’s not just “moodiness.” A dip in engagement usually points to something physical or emotional going on. Withdrawal like that often shows up in older pets or pets dealing with pain, but it can happen at any age when something’s not right internally.
10. Acting clingier than usual
Sometimes it’s not withdrawal—it’s the opposite. If your pet suddenly won’t leave your side, follows you into every room, or seems unusually needy, it might be a sign they’re feeling vulnerable or unwell. Clinginess can also stem from anxiety, especially if their routine has recently changed. Even boredom or cognitive changes in older pets can trigger it.
11. Sudden destruction or inappropriate chewing
If a pet that’s long past the chewing phase starts tearing up furniture or gnawing things they’ve never touched before, it’s not just bad behaviour—it’s communication. This might be anxiety, dental discomfort, or even hunger due to metabolism changes. Destructive habits often have deeper roots than just boredom.
12. Strange posture or movement
Limping, stiffness, arched backs, or holding their head at a weird angle—these are your pet’s version of saying, “something hurts.” These signs can come and go, which is why it’s easy to miss them early on. Watch how they move when they think no one’s watching. Subtle changes in how they sit, jump, or lie down are often the first clues.
13. Just feeling “off”
Sometimes there’s no big symptom—just a sense that your pet isn’t acting like themselves. Maybe they’re quieter. Maybe they’re sleeping in weird places. Maybe their eyes just don’t look right. If your gut says something’s wrong, trust it. You know your pet better than anyone else, and even small changes can be the first sign of something bigger. A vet check might bring peace of mind, or catch something early.